Civ5 bnw won't load this morning

Hi. Lots of problems with Civ5 this morning. First i had problems with steam, but after searching this forum and steam's i appear to have resolved that. But now, every time i try to start civ5 it goes through the motions and then, just at the point where it is about to give me the start screen, everything goes away and i am back to the desktop. it is not appearing as a process in my task manager, so it has completely quit. I tried deleting some cache files, as per a post from jan 31, but that did not help. Should i completely uninstall civ5 and reinstall? Thanks in advance for any help you can give!